Ref. 28009BABY twins Naomi and Nikita Eden will deliver a petition to Prime Minister Tony Blair tomorrow to highlight a child tax credit loophole said to leave parents of twins and triplets hundreds of pounds out of pocket.

The six-month-old sisters from Bradford on Avon will travel to Downing Street with mum Hannah Ede and a petition signed by 5,000 supporters of the campaign to get a fairer deal for families with multiple births.

According to the rules of the child tax system, families with twins are missing out on a one-off payment of £545 while families with triplets are missing out on an extra £1,000.

National charity The Twins and Multiple Births Association (Tamba) is backing the petition to stamp out what it describes as a fundamental inequality in the system.

Tamba director Helen Forbes said: "The Child Tax Credit is made up of three elements; the family element of £545, an amount payable per child dependent on household income, and an additional £545 baby element payable for the first year.

"This baby element is only payable for one baby at a time. This is wholly unfair. Families with twins, as opposed to two children born, say 18 months apart, are missing out on £545 and families with triplets or more are being short-changed by over £1,000."

Tamba wants other parents with twins or triplets in west Wiltshire to join them at 10 Downing Street, when they hand over the petition to Tony Blair tomorrow at 11.30am.

Miss Ede said: "Having twins brings additional emotional, practical and above all financial pressures and this is the latest blow from a Government that does not recognise the extra costs having a multiple birth family brings."

Sarah Cardy, manager of West Wiltshire Citizen's Advice Bureau, said it was likely the loophole would cause more problems in the future as more couples opt for fertility treatment increasing the likelihood of a multiple birth.

Ms Cardy said: "You have to remember that at the end of the day this is a tax allowance. Yes, people are losing out but we don't get many inquiries about it here."

There are approximately 10,000 multiple births in the UK every year and Tamba has calculated the cost to Government of closing the loophole and making the baby element payable per baby would be in the region of £5m a year.

Mrs Forbes said: "While Tamba welcomes the fact that the Government has recognised the additional costs that a baby brings, the needs of multiple birth families have clearly been overlooked because much of the extra costs of babies has to be simply duplicated, or triplicated, with multiples."